From what I understand, Neverwinter Nights 2 just has more DnD resources like monsters and whatnot, better graphics, more spells n shiz, and Mask of the Betrayer, which many people hail as one of the greatest RPG's in recent-ish gaming history.

I mostly bought it to try out persistent worlds/role play. Pretty good for that.

I've died like six times in Mask of the Betrayer because it's just me and my roommate, and we're apparently terrible at everything. Also I keep turning pausing off, so combat is basically the same as DnD combat, except you have to make split-second decisions.

I just downloaded NWN2 because I was jonesing for DnD3.5. Also I played Baldur's Gate waayyyyy back in the day so it feels pretty nostalgic. I got a couple of extra campaigns installed but so far I'm really just working through the first.